For best results strap cocktail shaker to penny farthing wheel and traverse cobbles. If this is impossible or you live in a historically unsympathetic area, then assemble small team of volunteers (we both know they're assistants). Combine ingredients in cocktail shaker without soda water. Add ice and shake vigorously for a number of minutes, passing shaker to assistants in case of exhaustion. After three minutes, pour into glass without ice and add a splash of soda water. One should be able to stand a straw up vertically in the frothy concoction. If this is achieved, raptourous congratulations are positively encouraged.